400fps is the limit most places for AEGs and 450 for Sniper rifles (unless you play indoors then is 350fps). Depending on what your doing between 350 and 450 is more than decent. The point is safety. There is other things you can do to make the rifle more accurate.

Practice and tactics help too. The rifle isn't everything. If you're just a crappy shot, or you make yourself an easy target-- it doesn't really matter how good your gun is.